Spring cushioned lift truck



Aug. 8, 1944. a. QUAYLE SPRING CUSHIONED LIFI' TRUCK Filed July 23, 19412 Sheets-Sheet 1 Menu INVENTOR I l i I l l BY .Z Q 42 z;

ATTORNEY 3, 1944- G. QUAYLE 2,355,328

SPRING CUSHIFONED LIFT TRUCK Filed July as, 1941 2 Sheets-Sheet z 1 III": /4

INVENTOR' ATTORNEY Patented Aug. 8, 1944 UNITED STATES PATENT OFFICE,

SPRING cusuromsn LIFT 'riwcx George Quayle, Philadelphia, Pa assignor toThe Yale & Towne Manufacturing Company, Stamford, Co'nn., a corporationof Connecticut Application July 23, 1941, Serial No. 403,646

7 Claims.

This invention relates to a lift truck of the type in which an elevatingframe or platform is lifted relatively to a main frame or lifting head,through operation of a suitable lifting mechanism. More particularly, myinvention relates to a truck of the type shown in my Patent No.2,309,138 issued January 26, 1943.

In trucks of the class described, it is customary a ram or other thrustimparting member may apply lifting pressure to the elevating platform.

As a feature of my invention, the lifting pressure of the ram is appliedthrough the medium of a spring. In this way, the load is elevated moresmoothly than might otherwise be possible. Also, since the platform of ahydraulic truck is preferably sustained in elevated position by the ramof the hydraulic lift unit, the spring through which the lifting thrustis applied serves to cushion the elevating platform relatively'to theram as the truck moves over a rough floor or other terrain.

As a more detailed feature of my invention, there is mounted on theelevating platform a movable thrust accepting member which is springpressed relatively to the elevating platform and is adapted, preferably,at one end thereof, to receive lifting thrust from the ram. Even moreparticularly, this member may be in the form of a disc or plunger,'withspring guiding means for the spring or springs which maintain it inspring pressed relation to the elevating platform.

As a further feature of my invention, the thrust accepting member ispreferably mounted in a cylindrical chamber formed on the elevatedplatform, and with a portion of the member in thrust accepting relationto the ram.

As a furtherfeature of my invention, the surface on the thrust acceptingmember which bears against the end of the ram, and the end surface ofthe ram itself, are formed so that pivotal movement between the twosurfaces is possible during the lifting operation, while slidingmovement between the two surfaces. is also possible to allow for suchweaving as may occur between the elevating frame and the main frame.

' I have thus described my invention generally in order that theconstruction which I shall herestood, and in order that my contributionto the art may be fully appreciated. It should be understood moreover,that any invention may be embodied in forms other than that herein shownand described, so that my patent claims should be sufficiently broad toprevent the utilization, with impunity, of my invention by others indifferent mechanical forms.

For a detailed description of my invention I shall now refer to thedrawingsi-n which Fig. 1 is an elevation of a truck of the type to whichmy invention may be applied. Fig. 2 is a vertical section taken alonglines 22 of Fig. 1. Fig. 3 is an enlarged vertical section through apart of Fig. 1 and illustrating the coaction between the thrust reeiving member and the upper end of the ram.

Referring now more particularly to the drawings, and especially Fig. 1,reference numeral ll indicates the lifting head of a hydraulic truck, onwhich is supported for pivotal movement a stee ing and lifting handleII, which through a vertical strut i2 rotates a lever l3 for actuating apump contained within the cylinder H of the hydraulic lift unit I5.

inafter describe in' detail, may be better underfor sliding and pivotalcoaction with a rounded lug IB depending from the disc portion is ofwhat I term a thrust receiving member. The disc i9 is formed for slidingmovement within a cylindrical bearing chamber 20 secured as by weldingor any other suitable way, to a vertically extending standard 2i of theelevating. platform 22. While I shOW a cylindrical chamber 20 which iscircular in cross section,'it should be well understood that thecylindrical chamber 20 may be of any other cross sectional shape, andthat the disc l9 may also be ofany suitable shape for cooperationtherewith.

Extending from the upper surface of the disc I8 is a pin 23 which servesas a guide for telescoping springs 24a and 24b which rest at one endagainst the disc l9 and at the other end against the surface" of thecylindrical cham ber 20. A suitable abutment 26 extends from the surface25 and serves to guide the upper ends of the springs 24a and 24b and tomaintain them in proper operating relation to the chamber 20. It willnow be appreciated by those skilled in the art that as ram l6 movesvertically to impart lifting pressure to the thrust receiving memberthrough the depending lug It, the thrust is in the thrust receivingmember, that maintains the elevating platform 22 in any elevatedposition to which it may be moved by the ram 3, the springs 24a and 2lbwill cushion the elevating platform relatively to the lifting head Itand ram |8 as the truck is moved over a rough terrain.

During the lifting operation it will be appreciated that there may besome lateral weaving between the lifting head l and ram It, on the oneside, and the elevating platform 22 and its vertical standard 2| on theother side. This weaving may take place without disturbing the mountingof the hydraulic lift unit is and its ram l8 due to the particularcoaction between the rounded surface of the depending lug l3, and theform of the surface I? of the ram l3. These surfaces are so formed thatsliding as well as pivotal movement between the ram i6 and the lug I!are possible. Those skilled in the art will apthrust receiving deviceand the end of said champreciate the value of this particularconstruction.

While the general construction of my lift truck does not form part ofthis invention it is thought best to outline the relation of the severalparts thereof whereby the elevating platform is lifted relatively to thelifting head as thrust is imparted thereto by the ram it .through theintermediary of the depending lug l3, disc l9 and th springs 24a and24b.

The upper end of the standard 2| is pivotally connected to the upper endof the lifting head l0 through upper links pivoted at 3| to the standard2| and at 32 to the upper end of the lifting head i0. Lower links 33 arepivoted to the elevating platform at 34, and through a shaft 35 to thelower portion of the lifting head l0. As the elevating platform is movedvertically on the links 33 and 33 relatively to the lifting head,

the links 33 are rotated in a clockwise direction. In so rotating, theywill move to the right the rods 36 pivoted thereto at 37. The rods 36are in turn connected to the rear links 38 which carry the rear wheels39. Pull on the rods 36 causes rotation of the links 38 about the pivotshaft whereby to raise the rear end of the platform 22 on the wheels,39, this lifting being simultaneous with the lifting of the forward endof the platform on the upper and lower links 30 and 33 respectively. I

The hydraulic unit If: is itself pivoted on the. same shaft 35 throughwhich the links 33 are pivotally connected to the lifting head it. Theentire hydraulic lifting unit 15 may therefore pivot freely relativelyto the lifting head, while the ram i6 pivots freely relatively to thelug l3 of the thrust receiving member, to follow the upward movement ofthe elevating platform. It is thought that the brief description thusgiven is sufficient to set forth the relation of my invention hereinclaimed to the type of truck in which it may be utilized. For a moredetailed description of the particular type of truck, reference may behad to my earlier application supra.

I now claim:

1. In a truck of the class described, a main frame, an elevating frame,means mounting said elevating frame for upward lifting movementrelatively to said main frame, a hydraulic lift unit pivoted at itslower end on said main frame, a ram forming part of said hydraulic unitexbar and throughwhich lifting movement is imparted to said elevatingframe by said ram and thrust receiving device.

2. In a truck of the class described, a main frame, an elevating framehaving a vertical standard, a cylindrical chamber formed on the upperend of said standard, a thrust receiving plunger mounted for slidingmovement in said cylindrical chamber, a hydraulic lift unit pivoted atits lower end on said main frame, a ram forming part of said lift unitand bearing at its upper end against the lower end of said plunger, anda spring interposed between the upper end of said plunger and saidelevating frame and through which lifting movement is imparted to saidelevating frame by said ram and plunger.

3. In a truck of the class described, a main frame, an elevating framehaving a vertical standard, a'cylindrical chamber. formed on the upperend of said standard, a thrust receiving wplunger mounted for slidingmovement in said cylindrical chamber, a hydraulic lift unit pivoted atits lower end on said main frame, a ram forming part of said lift unitand hearing at its upper end against 'the lower end of said plunger, theupper end of said ram and the lower end of said plunger being formed toallow pivotal and sliding movement between said ram and said plunger.

4. In a truck of the class described, a main frame, an elevating frame,means mounting said elevating frame for upward lifting movementrelchamber formed on said elevating frame, a thrust receiving deviceslidably mounted in said chambar and bearing at its lower end on theupper end of said thrust member, and a spring in said chamber interposedbetween said thrust receiving device and the end of said chamber andthrough which lifting movement is imparted to said elevating frame bysaid thrust member and thrust receiving device.

5. In a truck of theclass described, a main frame, an elevating frame,means mounting said elevating frame for upward lifting movementrelatively to said main frame, a thrust mechanism mounted on said mainframe, a thrust member forming a part of said thrust mechanism andmovable relatively thereto when imparting lifting movement to saidelevating frame, a thrust receiving device mounted for movement on saidelevating frame and spring pressed relatively to said elevating frameand against said thrust member, whereby said thrust member impartslifting .movement to said elevating frame through the medium of saidthrust receiving device and said spring.

6. In a truck of the class described, a main frame, an elevating frame,means mounting said elevating frame for upward lifting movement rel- Iatively tosaid main frame, a hydraulic lift unit assasas frame andmovable relatively to said hydraulic lift unit to raise said elevatingframe, a thrust 7 receiving plunger, means mounting said plunger formovement relatively to a part of said elevating frame, the'lower end ofsaid plunger bearing against the upper end of said ram, and a springinterposed between a part of said plunger and said elevating frame foryieldingly resisting movement of said plunger on said "mounting meansrelatively tosaid elevating frame, the lifting movement of said ramimparting lifting movement to saidelevating frame through the -medium ofsaid plunger and said interposed spring.

7. In a truck of the class described, a main frame an elevating frame,means mounting said elevating frame for upward lifting movement-rel,

' atively to said main frame, a hydraulic lift unitpivoted at its lowerend on said main frame for vertical swinging movement on an axis transverse of the truck, a ram forming part of said hydraulic unit extendingvertically upwardly toward said elevating frame, a thrust receivingdevice having a surface against which bears the upper end of said ram,means whereby said thrust receiving device is movably mounted relativelyto said elevating frame, and a spring between said thrust receivingdevice and said elevating frame for yieldingly resisting movement ofsaid thrust receiving device relatively to said elevating frame whensaid ram imparts thrust to said thrust receiving device.

-' GEORGE QUAYLE.

